1. Field of the Invention
This invention relates to improvements in liquid-gas separator units that are adapted for use with downhole oil well pumps to separate gas from the liquid to be pumped from the well.
2. Description of the Prior Art
Liquid-gas separator units are used downhole in oil producing wells to perform the task of separating gas from well liquid before it is pumped out of the wells. Any significant amount of free gas present in undissolved form in an oil producing well hinders the pumping of the well liquid, which may include other liquids in addition to crude oil, out of the well. Various U.S. patents, such as U.S. Pat. No. 2,104,339 to Arutinoff, U.S. Pat. No. 2,311,963 to Pyle, U.S. Pat. No. 2,285,169 to Pyle and U.S. Pat. No. 3,624,822 to Carle, describe liquid-gas separator units and provide information as to why such units are used. As evidenced by these patents, there are different kinds of units that work according to different physical principles, and their performance characteristics, as might be expected, depend upon their particular features. There does not appear to be any particular unit, of which applicant is aware, that is not limited, in one way or another, in its performance capabilities.
A superior separator unit, in general, is one that is capable of discharging liquid at a high flow rate, after separating free or undissolved gas from the liquid, to provide relatively gas free liquid. Moreover, a superior liquid-gas separator unit can function to separate widely varying quantities of free gas, ranging from negligible gas flow rates constituting negligible proportions of a liquid flow rate up to large gas flow rates corresponding to several times the liquid flow rate, without any significant change (i.e., decrease) in the liquid flow rate through the unit and, in addition, can perform the separation function with essentially negligible gas carryover in the liquid discharged from the unit. Inherently, a high performance unit is one which efficiently separates gas from liquid and discharges liquid which has only a relatively small amount of undissolved gas remaining therein, because significant quantities of free gas in the discharged liquid may hinder efficient pumping of liquid from a well in which such a unit is utilized. A truly superior unit is capable of effective use in wells wherein large quantities of undissolved gas are present in the well liquid.